Improvement in slide-valves



'UNITED STATES PATENT OFFICEO ALEXANDER BUOHANAN, OF NEW YORK, N. Y.

IMPROVEMENT IN SLIDE-VALVES.

Specification forming part of Letters Patent No. 50,331, dated October 10, 1865 antedated September 30, 1865.

To all whom it may concern:

Be itknown that I, ALEXANDER BUCHANAN, of the city, county, and State of New York, have invented a new and useful Improvement in Means of Relieving the Slide-Valves of Engiues from Excessive Pressure; and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming part of this specification, in which- Figure l is a central longitudinal vertical section of a valve-chest, slide-valve, and their appurtenances, illustrating my invention. Fig. 2 is a transverse vertical section of the same. Fig. 3 is a plan.

Similar letters of reference indicate corresponding parts in the several figures.

This :invention relates to the use of a flexible valve-cover attached to the iniiexible cover of the valve-chest, for the purpose of protecting the back of the slide-valve to as great an extent as desired from the pressure of the steam in the chest.

It consists in a novel construction of the said lexible cover, a novel mode of attaching the same to the inflexible cover of the valvechest, and certain novel means of adjusting the same and keeping it in place, whereby great facility is afforded for the necessary adjustments, and all liability to corrosion of the parts is obviated.

To enable others skilled in the art to make and apply my invention, I will proceed to describe it with reference to the drawings.

A is the valve-chest; B, the inflexible cover yof the same; C, the slide-valve, and a the valve-seat.

The valve has its back surface planed or otherwise finished up parallel with its face. There is an opening, b', in the back communieating with its central exhaust-cavity, b, and it has flanges c c at its ends to increase the length of its back. In other respects itis substantiallylike slide-valves commonly used, and yin the respects above mentioned it resembles some of what are termed balanced valves.77 VIt is operated in the usual manner by an eccentric or any suitable valve-gear connected with its stem t.

D, E, and E are the principal parts of the exible valve-cover. The part D is a quadranguiar frame, of cast-iron, brass, or other metal,

of a width equal to the width of the valve, and of alength equal to the distance between the outer edges ofthe ports d d in the valve-seat. Its lower face is planed or otherwise nished up to a iiat surface to fit the back of the valve, and its upper face is planed or otherwise iinished parallel with the lower one. The part E consists of a thin exible elastic plate, of

steel or other suitable metal, the margin of which is clamped to the frame D by means of screws e c or rivets and a clamping-piece, j'. The part F consists of an inflexible plate secured to the under side of the flexible plate E. rlhis plate F is of a form corresponding with the interior of the frame D, but cfa size sufciently smaller to allow it to Work up and down freely within the said frame without touching, and its object is to confine the iiexibility ot' the plate E near the interior ofthe frame D.

In order to obtain the necessary degree of iiexibility of the plate E, the inner edge of the Lipper side of the frame D is beveled or rounded off, as shown at g g in Figs. l and 2, and the outer edge of the upper side of the plate F is beveled or rounded off in a similar manner, as shown at It h in the same iigures, and to prevent corrosion between the plate E and the frame D the edge ot' the plate E is beveled or rounded off on the under side, as shown at it, so as to make the edge quite thin or sharp.

The plate F is secured closely to theiiiexible plate E by means of screw-threads dk k and nuts j j on the lower parts of the four pfependicular standing bolts Gr G, by which the lexible valvecover is attached to the iniexible steam-chest cover. These bolts pass through holes in the plate E and screw into tapped holes in the plate F, and the nutsjj, which are fitted to the screwthreads 7c lc above the plate F, are screwed so tightly down on the latter plate as to prevent any leakage of steam around the bolts through the holes in the said plate, and thus entirely exclude the steam in the chest from the under side of t-he valve-cover. The standing bolts Gr Gr pass through holes, l l, Fig. 2, in the indexible valve-chest cover B, the said holes being large enough to give plentyofclearance around the bolts to allow the cover B to be easily taken oif and put on the valve-chest without any danger ofjamming or straining the said bolts, and

. to allow the exible cover to be set in its proper position over the valve without coming inl contact with the sides oi the said holes, the. said proper position being such that the said cover occupies a central position over the parts d d.

Seats m m, Fig. 2, are formed upon the eX- terior of the chest-cover B, and faced parallel with the valveseat,to form bearings for the under faces ofthe broad ilangedy bottoms of the adjusting-nuts H H, which are fitted to screwthreads a n on the upper parts of the said standing bolts, the said faces being scraped or ground with emery to iit the said seats m m so that the said nuts may form steamtight valvelike joints with the said seats when held down by clamping-pieces I I and screw-bolts J J, and thus prevent leakage through the holes Zt in the cover B.

The clamping-pieces I I, two in number, consist of arched bars, each of which bears upon i the ilangespp of two of the nuts H H, both -ends beingt'orked to embrace the circular necks oi' the two nuts, as shown at q g in Fig. 8. 011e bolt'J, inserted through a hole in the center of each clampingpiece and screwed into a tapped hole in the cover B, makes the clampingpiece hold down the two nuts firmly upon their seats an m.Y

Above the nuts H H nuts r r are applied to the screw -threads n a, with india-rubber washers ks s below them, the said nuts fr r serving to tighten the said washers in such a manner as to around the threads of the bolts G G.

The nuts H H support the bolts G G and the ilexible valve-cover, and by turning the said nuts the bolts and valve-cover are adjusted in such a manner that when the pressure ofstealn comes on the back'of the said coverit will just keep its frame D in steam-tight contact with the back of the valve, without allowing the Vpressure of steam on the back oi' the said cover to produce any considerable pressure or friction ofthe said frame on the back ot the valve. By tting the nuts H H to seats m in, and providingadditional nuts r 1' and indiarubher washers s s on the bolts G G the adjustment is provided for without the use of either stuft'- ing-boxes of caps t0 cover the adj usting-bolts, as are used with other methods of supporting and adjusting the'valve-cover.

The fra-me D of the iiexible cover is tree to rise with the valvein case of any compression of steam on the exhaust side of the piston, or in case of workin g water in the cylinder, or when from any cause it becomes necessary; but it is desirable to prevent the said lframe from rising so high as to strain the iiexible plate E; and in order to effect this two or more guard-bolts, K K, are screwed through the inflexible cover B of the chest in such positions that their lower or inner ends will serve as stops to the said frame. These bolts are adjustable by a wrench outside of the cover B,- and their adjustment is secured by jam-nuts u u, screwed down upon the cover B.

preventany leakage of steam The lieveling or rounding ofthe' edges oi' the frame 4D and plate F, as shown at g and h, renders the plate E less liable to fracture than if the said frame I) and plate F presented square edges to the said flexible plate E. It also obviates the necessity for frequent adjustment of the iiexible cover to compensate for wear of, the Valve by allowing the frame D to vfollow further thelwear ot" the valve-faces, and

enables the said frame to rise more easily when the valve lifts from its seat.

The ileXible valve-cover is kept in proper position lengthwise ofthe valve-chestby means of four adjustable bars, L L, arranged parallel with the valve-seat, two screwed into tapped holes in one end of the valve-chest and two into similar holes in the other end, and secured by jamhuts o c outside. The inner ends of these hars, which come in contact with the frame D of the valve-cover, are slightly rounded. These bars have their outer ends formed to receive a wrench, by which, 'when the jamnuts are slackened, they can be screwed in or out to adjust the flexible cover to the desired position over the ports. The said bars pass through and fit easily into stationary guides w w, secured to the sides of the valve-chest for the purpose of steadying them.

In one side of the valve-chest, opposite to the flexible valvecover and back of the valves, there are two peep-holes, w m, through .which `to examine the position of the saidfvalve-cover.`

These holes are fitted with tight screw-plugs y y, which are only removed when it is desired to adjust the valve and when steam is shut oft' from the valve-chest.

The method of applying and adjusting the iilexible valve-cover and its appurtenances is as follows: The valve being in its seat, the adjust-able bars L L are inserted lthrough the guides w w, and screwed through the ends of the chest from the inside. The dexible cover, having the standing bolts G G secured in it, is then placed on the back of the valve and brought to its proper position, which is over the center ofthe throw of the valve. The bars L L are next adj usted to bring their inner ends into contact with the frame D ot1 the valve cover without either binding or allowing play orlongitudinal movement of the said cover, and the jam-nuts 'u are then screwed up to secure this adjustment. The chest-cover B is next put on and screwed down, the standing bolts G G passing freely .through the roomy holes Z l provided therein. The flanged nuts H H are then put on the standing bolts G G and run downas far as the seats m m. A light now being held to one of the peep-holes .rx enables the engineer looking through the other one to see the valve and exible cover, and he turns the nuts H H in a direction to raise the flexible cover from the back of the valve, adA justing the cover to make the frame D nearly touch the valve. When this adjustment has been made the guard-bolts K K are adjusted the clamping-pieces I I are' and secured, and

put on and screwed down by the bolts J J to secure the nuts H H, and the nuts 1' fr and the washers s s are put on and screwed down. The flexible cover may require afurther adjustment by means of the nuts H H after the engine has been heated by the steam.

What I claim as my invention, and desire to secure by Letters Patent, is-

1. The attachment of theflexible valveeover to the inflexible cover of the steam-chest by standingboltsGGandlangednutsHH,which are fitted to form steam-tightbearings on seats m m outside of the latter cover, substantially as herein specified.

2. The clamping-pieces I I and bolts J J, in combination with the anged nuts H H, standing bolts Gr G, valve-Chest cover B, and ilexible valve-cover, substantially as and for the purpose herein specified.

ALEXR. BUCHANAN.

Witnesses HENRY T. BROWN, J. W. CooMBs. 

